An indigenous Mexican corn gets its nitrogen from the air.

For thousands of years, people from Sierra Mixe, a mountainous region in southern Mexico, have been cultivating an unusual variety of giant corn. They grow the crop on soils that are poor in nitrogen—an essential nutrient—and they barely use any additional fertilizer. And yet, their corn towers over conventional varieties, reaching heights of more than 16 feet.  

A team of researchers led by Alan Bennett from UC Davis has shown that the secret of the corn’s success lies in its aerial roots—necklaces of finger-sized, rhubarb-red tubes that encircle the stem. These roots drip with a thick, clear, glistening mucus that’s loaded with bacteria. Thanks to these microbes, the corn can fertilize itself by pulling nitrogen directly from the surrounding air.

The Sierra Mixe corn takes eight months to mature—too long to make it commercially useful.